Shaped charge designs in present use (i.e., in weapon systems, oil well completion, or drilling operations) may be designed to provide a deep hole in a target material and maximize crater volume. Such shaped charge configurations achieve maximum penetration by projecting a continuous rod or a stream of particles, in near perfect alignment, against a target material. Since penetration is directly proportional to the length of the penetrator, care is taken to maximize the jet length and to keep jet particles well aligned. This concept results in deep holes, of relatively small diameter, in a target.
However, certain applications may require attack of relatively thin targets (i.e., materials of low strength and small thicknesses). Conventional shaped charges do relatively little damage against such targets. For example, a shaped charge fired against a lightly armored vehicle will do minimal ballistic damage. The jet will perforate such a vehicle leaving only a small entrance and exit hole. Against targets of this type, it may be advantageous to reduce the effective depth of penetration and spread the impacting penetrator jet over a wider surface area to maximize the total damage to the target. This type of damage may be obtained by dispersing the jet in a radial fashion to increase the surface area impacted by the jet.
In addition, it may be desirable to provide a particular jet pattern for particular types of targets. For example, when using a shaped charge to destroy a missile or the like, a particular pattern may be desirable to insure that at least a portion of the penetrator jet impacts the missile.
Moreover, it may be desirable to provide a shaped charge round which may be selectively provided with either aligned and dispersed jets. The use of a single round type to provide both types of charges may reduce inventory costs significantly and allow for selection, in the field, of charge type for a given round. In addition, the use of a same or similar charge type for both aligned and dispersed jets may reduce manufacturing costs of such charges due to the economies of scale in manufacturing a common charge design.
FIG. 1 is a cross section view of a prior art shaped charge round. Explosive fill 10 within casing 24 surrounds a hollow cavity made by liner 15. Casing 24 may comprise a metallic (e.g., thin aluminum or steel) or non-metallic (e.g., composite graphite, plastic, cardboard or the like). Alternatively, no casing may be provided for example, for a static charge fired from a stationary position.
Liner 15 is illustrated in FIG. 1 as a conical insert with a thin wall although any arcuate geometry may be used depending on desired result. Casing 24 may be a regular cylinder or may take other forms (e.g., tapered or boat-tailed cylinder). The shaped charge round of FIG. 1 may be typically point initiated by a booster/detonator assembly 18 located along an axis of revolution of the round.
The shaped charge round of FIG. 1 may be incorporated into an artillery shell, mortar shell, missile (e.g., surface to air missile, wire guided missile, air to air missile, or the like) or may be incorporated into charges used for industrial purposes (e.g., oil exploration, mining, explosive welding, or the like).
Once the round of FIG. 1 has been detonated, liner 15 collapses to form a high speed jet. The use of liner 15 is described, for example, in H. Mohaupt, U.S. Pat. No. 2,419,414, issued Apr. 22, 1947, incorporated herein by reference.